Drying kiln



May 15, 1951 c. R. GUTHRIE DRYING KILN '2 Sheets-Sheet 1 Filed March 3l,1948 May 15, 1951 c. R. GUTHRIEy 2,553,452

DRYING KILN Filed March 5l. 1948 A 2 Sheets-Sheet 2 Patented May 15,1951 UNITED STATES PATENT OFFICE 3 Claims.

The invention relates to drying kilns and an l object of the inventionis to provide a kiln comprising a specially designed building consistingof a steel frame and enclosed by insulated aluminum panels and doorsarranged in such a manner that they do not obstruct or interfere withthe predetermined currents of air created in said kiln building.

Another object of the invention is to provide a kiln of the characterindicated above, the building of which contains the necessary apparatusfor heating the air in said building comprising a fan or a blower to setthe air into motion to flow through prearranged ducts and air Ways whilebeing directed by baffles.

A further object of my invention is to provide a kiln of the characterindicated above, in which inlet dampers are automatically opened topermit a predetermined amount of fresh air to enter, when the useddrying air contains a predetermined amount of moisture.

A still further object of the invention is to provide a kiln of thecharacter indicated above, which is equipped with outlet dampersdischarging any superuous amount of air from the kiln.

Another object of my invention is to provide a kiln of the characterindicated, in which the mixture of fresh air and pre-used drying air isforced through a humidifying chamber, where a controlled amount ofhumidity may be added to said air mixture before it starts again itscircuit through the kiln.

Other objects of the invention may appear in the following specicationdescribing it with reference to the accompanying drawing illustrating apreferred embodiment of the invention. It is, however, to be understoodthat the inven tion is not to be limited or restricted to the exactconstruction and combination of parts described in the specification andshown in the drawing, but that such changes and modifications may bemade, which fall within the scope of the claims appended hereto.

In order that the invention may be better understood I will now proceedto describe it with reference to the accompanying drawing, in theseveral iigures of which similar parts are indicated by similarreference characters and in which:

Figure l is a diagrammatical View showing a longitudinal section throughthe kiln according to the invention.

Figure 2 is a sectional view taken on line 2--2 in Figure 1 Figure 3 isa sectional view taken on line 3-3 in. Figure 1.

Figure 4 is an elevational outside view of a Wall of the drying kilnaccording to the invention, and

Figure 5 is a sectional view in a larger scale and taken on line 5--5 inFigure 4.

The drying kiln embodied herein comprises a building B of preferablyelongated rectangular shape, on the floor IB of which a plurality ofcomparatively long spacers lI are arranged parallel to each other andlongitudinally of the building B. The spacers are spaced from each otherat such a distance that each pair of adjacent pair parallel spacers isadapted to support a plurality of boards I2 or the like extendingtransversely of the building and parallel to each other and spaced apartfrom each other as shown at I 3. On top of these boards some morespacers II are placed longitudinally of the building and parallel to andspaced apart from eac/h other, and another tier of boards I2 or the likeis arranged on top of each pair of the spacers resting on the firstdescribed tier of boards. The boards in the second tier extend alsotransversely of the building and parallel to each other and are spacedfrom each other as shown. The stacks I5 of boards are arranged so thatone end of one stack is located as a comparatively short distance fromthe end wall Ill of the building, that a space I5 is left betweenadjoining stacks and that there is also a space between the stacks andeach of the longitudinal walls I6 of the building B. A partition I'Iextends transversely across the building and divides it into a drierroom I3 and a heater room I9. There is left a space 2B between thepartition Il' and the adjacent stack of boards.

In the heater room I9 an air heating device 2I of any preferredconventional kind and construction is arranged, which may heat airpassing therethrough either by means of oil, coal, high pressure steamcoil or the like. A fan 22 sucks the heated air out of the heater andblows it through a supply duct 23, which extends upwardly through theceiling 24 of the building B and horizontally and longitudinally in theattic 25 between the ceiling and the roof 25. On the inner end portionof the supply duct a pair of branch ducts Z'la are arranged, whichextend downwardly through the ceiling 24 into the drier room I8approximately centrally between the end wall I4 and the partition I'l.On the end portion of each branch duct two high velocity registers orair nozzles 2lb are mounted at a level above the top tier of the boardsI2. The nozzles are arranged so that they expel heated air toward theend Wall I4 and the partition I1 and the expelling force is such thatthe expelled air hits the wall and the partition without coming intodirect contact with the stacked lumber. The heated air is then deflectedtoward the iioor Ii), thus building up a pressure. To prevent the heatedair from flowing around the stacks S narrow vertical baiiles 28 arearranged on the longitudinal side Walls I6, so that they projectinwardly therefrom and abut the outer corner portions of the stackedboards. Between the boards located adjacent the space l a baille plate2g is arranged adjacent each side wall l and closing the ends of the'space I5. The heated air, which is expelledthrough the nozzles 2lbflows therefore through the spaces formed by the spacers ll between thestacked g boards toward the center as indicated by the arrow heads inFigure 1.

In the central space l5 a portion of the heated air flows upwardly,where it combines with the air being expelled from the nozzles 2l. Thebiggest portion of the air in the space E5 is sucked by the force of thefan 22 through an opening 3U in the oor 0 into a return duct 3| arrangedunderneath the oor. This return duct is connected with a mixing chamber32 located in the heater room I9. An air inlet 33 extending through theroof 26 is normally closed at its bottom end by dampers 34 preventingfresh air from entering the mixing chamber. When, the return air hasabsorbed enough moisture from the lumber Vbeing dried to contain apredetermined amount of moisture, the dampers are opened by anyconventional means, such as an electro-magnet for instance, controlledby a conventional hygrostat 35 or the like. The entering fresh air mixeswith a portion of the air flowing through the return duct. The air inthe mixing chamber is sucked by the fan 22 through a duct 3E into ahumidifying f chamber 31. Here the mixed air is further humidied to apredetermined degree, if required, by conventional hygrostat controlmeans (not shown). From there the air is drawn into and The superfluousportion of the return air through the heater 2i for another cycle. L

passes the entrance to the mixing chamber 32 and keeps on flowingthrough the return duct '31, which extends beyond the end wall 38 of theheater room I9 and Yprojects then upwardly and outwardly as indicated at39 and d!) respectively. The end opening of the return duct portion 40may be closed by outlet damper 4|. A drain pipe 42 is connected with thereturn duct 3l and leads to a pit 43 so that any condensed water col Ylecting in said return duct ows off through said drain pipe.

To make the above described drying kiln highly effective, it isnecessary to build up a certain amount of pressure, so that the heatwill pene-gA trate the lumber better to open the pores and to start thesap to flow more freely.l To attain this object the building B isconstructed as 'follows:

A frame F' consists of a plurality of verticalA low rbodies from twosheets 45 of aluminum, which are connected with each other by end andside walls, lconsisting each of a strip of aluminum. The hollow in eachof these bodies is lled with 4 any preferred heat insulating material41. The panels are secured to the vertical frame members by carriagebolts 48 slipped into the slot 45 and extending through said slots andbetween two adjacent panels P held against the inside or slotted face ofthe frame member. An elongated plate 49 of aluminum is provided with aplurality of equidistantly spaced holes 50 permitting the bolts 48 toextend therethrough. Nuts 5I on said bolts force the plates 49clampingly against the panels P and hold them in position. Any openspaces in the walls constructed, as described above, are lled with anypreferred conventional mastic. The walls may be reinforced by crossframe members 52 extending transversely between the vertical framemembers 44.

-The above description shows clearly that a kiln building of thecharacter described eliminates all obstructions adapted to cause anydeflection of the air currents, since all the panels are secured on theinside of the frame members.

I claim: y

1. A lumber drying kiln, comprisingan elongated building including endand side walls, a floor and a roof, a transverse partition dividing theinterior of the building into a drying room and a smaller heater room, aceiling extending above the two rooms to provide an attic between thesame and the roof, a heater within said heater room, an air mixingchamber within said heater room and communicating with said heater, anair inlet depending through the roof and said ceiling and communicatingwith said mixing chamber, a main duct extending from said heater throughsaid ceiling and the attic to a point above the approximate center ofsaid drying room, a branch duct extending transversely from the free endof said main duct, nozzles extending from the opposite sides of saidbranch duct, a suction fan mounted within said heater adjacent the inletend of said main duct for forcing the heated air through the latter tosaid nozzles, said nozzles being adapted to discharge the heated airlaterally therefrom toward the opposite ends of said drying room for itscirculation over and back through lumber arranged in spaced tiers withinthe latter,` an air return duct extending beneath the floor and openingtherethrough at the approximate center of said drying room, and a secondbranch duct extending upwardly through the floor into said heater roomfrom said -return duct and communicating with said mixing chamber.

2. The invention as dened in claim l, with .the saidreturn duct havingits outlet end extending beyond the second branch duct and the 'outerend wall of said heater room, said outer opening to atmosphere by way ofan upwardly and outwardly angled extension thereof, damper means mountedwithin said extension, and a drain leading from said return duct at thelower end of said extension.

3. The invention as dened in claim 1, with Va 'humidifying chamberinterposed between said air mixing chamber and said heater, damper meansmounted within said air inletV adjacent its point of connection withsaid air mixing chamber, and a hygrostaticcontrol means within saidmixing chamber for regulating the admission of fresh air thereto.

CLIFFORD R.

- (References on following page) REFERENCES CITED The followingreferences are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 638,831 Barbour Dec. 12, 1899895,620 Dejonge Aug. 11, 1908 1,330,238 Carrier Feb. 10, 1920 NumberNumber Name Date Carrier Oct. 11, 1921 Hirt Oct. 17, 1922 Cobb Oct. 14,1930 Polderman May 4, 1937 FOREIGN PATENTS Country Date France July 8,'1922

